1. Field of the Invention
The invention relates to a recording or reproduction apparatus with a holding and removing device for disc-type recording medium which retains or releases the recording medium with means provided on the disc turntable.
2. Related Art
Disc turntables with a hub penetrating through a centring hole in the recording medium in recording or reproduction apparatuses which have means for retaining the recording medium on the disc turntable have been known for a long time. Thus, as early as in DE-U 7005274, a mount for records was proposed, which holds a record both radially outwardly and downwardly on the disc turntable. Corresponding embodiments of the known mount for records are illustrated in FIGS. 1 to 4. Individual spring elements are arranged at the periphery of the hub of the disc turntable, the record being pressed onto the disc turntable in the centering hole by the said spring elements. Balls are provided as spring elements, which balls partly project through openings at the periphery of the hub and, at the inwardly projecting part, bear resiliently on a rubber body. What is disadvantageous is that a force required to overcome the spring resistance has the same magnitude in both directions, that is to say during emplacement and removal of the recording medium, and different spring forces are generated by a rubber body on account of fatigue phenomena and environmental influences.
Rising rotational speeds at which the recording medium rotates during recording or reproduction necessitate a larger holding force, which then leads to is advantageous flexural loading on the recording medium during the emplacement or removal of the recording medium.
As an alternative, in the case of a disc turntable composed of plastic capable of being injection-moulded, tongue-shaped springs are provided in radial slots at the periphery of the hub, the undercut limb end of which springs projects radially above the periphery of the hub and is at a distance from the disc turntable corresponding to the thickness of the record. During the emplacement of the record, the tongue-shaped springs spring back and then settle on the record. The recording medium can be removed only by applying a force perpendicularly to the direction of movement of the disc turntable, thereby rendering interchangeability of the recording medium more difficult. Tolerances of the centering hole of the recording medium are not compensated for by the mount.
The object of the invention is to provide a recording or reproduction apparatus with a holding and removing device for disc-type recording media which enables the recording medium to be emplaced and removed with forces that are to be applied exclusively in the directions of movement, compensates for tolerances of the centering hole of the recording medium, applies a constant holding force even over a relatively long period of time, and has a small number of individual parts.
This object is achieved by means which are specified in independent claims; advantageous designs and developments are specified in dependent claims.
It is an aspect of the invention that despite a comparatively small force during the emplacement and removal of the recording medium, the recording medium is held on the disc turntable with a large force and, to that end, a device is specified which comprises a small number of individual parts.
According to the invention, a holding and removing device for disc-type recording media is formed by a cover which closes off the pot-shaped hub of the disc turntable and is provided for the purpose of reducing the force with which the recording medium is held on the disc turntable. For this purpose, the cover has a restoring means which is provided on its edge and is provided for the purpose of withdrawing means that hold the recording medium on the disc turntable. The restoring means comprises a collar which is provided on the edge of the cover and is arranged in a manner such that it engages over the means provided for holding the recording medium on the disc turntable. Pressing the cover in a direction which is directed at the disc turntable has the result that the means holding the recording medium on the disc turntable are guided back and, in an advantageous manner, a force which is necessary to overcome the holding force of the recording medium during emplacement or removal is thereby reduced.
The means that hold the recording medium on the disc turntable are preferably balls or lugs which are arranged in a spring-elastic manner with a spring toothed disc in the pot-shaped hub of the disc turntable and by which the recording medium is held and centered on the disc turntable.
The cover that forms the holding and removing device is preferably guided on an inner hub of the pot-shaped hub of the disc turntable and is guided back into its starting position after actuation with a force that is likewise applied by the spring toothed disc. Since the cover is actuated in the direction of the disc turntable, during the emplacement or removal of the recording medium it is not necessary additionally to apply a force directed perpendicularly to the direction of movement of the recording medium, whereby the removal of the recording medium from the disc turntable is signficantly facilitated compared with known designs.
Tolerances of the centering hole of the recording medium are compensated for by the holding means formed by balls or lugs and, by virtue of the particular configuration of the cover that closes off the pot-shaped hub of the disc turntable, no additional individual parts are necessary in comparison with disc turntables having the same structure.
The holding and removing device comprises a small number of individual parts, enables the emplacement and removal of the recording medium with a force that is directed in the direction of movement of the recording medium, and, with a spring toothed disc preferably produced from phosphor-bronze or spring strip steel, ensures a constant holding force even over a relatively long period of time.
The recording medium can be held on the disc turntable with a large force and disadvantageous bending of the recording medium during emplacement or removal is avoided in an advantageous manner by the holding force being reduced.
In a recording or reproduction apparatus with a holding and removing device for disc-type recording media which retains or releases the recording medium with means provided on the disc turntable, the disc turntable then comprises, in accordance with a first embodiment, a
pot-shaped hub which is designed integrally with a surface that forms a bearing surface for the recording medium,
balls which hold the recording medium and are arranged in a spring-elastic manner in the pot-shaped hub with a spring toothed disc,
the spring toothed disc and
a cover which is advantageously used as a holding and removing device.
The number of individual parts required may be reduced further, in accordance with a second embodiment, if pot-type springs are used for holding the recording medium. The cover forming the holding and removing device preferably has latching webs with which it is anchored laterally in the pot-shaped hub. After the cover has been mounted, it latches into lateral recesses in the pot-shaped hub, which limit a movement of the cover directed away from the disc turntable yet nonetheless enable a movement of the cover directed towards the disc turntable. As a result of the movement or pressing of the cover in the direction of the disc turntable, the means holding the recording medium, with a restoring means that is provided on the edge of the cover and is provided in a manner such that it engages over the holding means, are guided back in the direction towards the center of the disc turntable and, as a result, the recording medium is released or it can be emplaced without resistance.